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Acquisition of Business - Narrative (Details) - Atlas Financial Holdings - Paratransit Business - USD ($) shares in Millions, $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 | Jun. 10, 2019
Business Acquisition [Line Items] |  |
Gross written premiums eligible for renewal | $ 110 |
Business acquisition, price as a percent of gross written premiums |  | 15.00%
Warrant term to acquire shares |  | 5 years
Number of shares able to be acquired with the warrant |  | 2.4
Maximum | Equity securities | Public company warrants |  |
Business Acquisition [Line Items] |  |
Fair value of warrant on date received |  | $ 1

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